/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.option;

import java.util.logging.Logger;

import javax.xml.stream.XMLStreamException;

import net.sf.freecol.common.io.FreeColXMLReader;
import net.sf.freecol.common.model.FreeColObject;
import net.sf.freecol.common.model.Specification;


/**
 * The super class of all options.  GUI components making use of this
 * class can refer to its name and shortDescription properties.  The
 * complete keys of these properties consist of the identifier of the
 * option group (if any), followed by a "."  unless the option group
 * is null, followed by the identifier of the option object, followed
 * by a ".", followed by "name" or "shortDescription".
 */
public abstract class AbstractOption< T > extends FreeColObject
        implements Option< T >
{

    private static final Logger logger = Logger.getLogger( AbstractOption.class.getName( ) );

    /** The option group prefix. */
    private String optionGroup = "";

    /**
     * Determine if the option has been defined.  When defined an
     * option won't change when a default value is read from an XML file.
     */
    protected boolean isDefined = false;


    /**
     * Creates a new <code>AbstractOption</code>.
     *
     * @param id The object identifier.
     */
    public AbstractOption( String id )
    {
        setId( id );
    }

    /**
     * Creates a new <code>AbstractOption</code>.
     *
     * @param specification The <code>Specification</code> to refer to.
     */
    public AbstractOption( Specification specification )
    {
        this( null, specification );
    }

    /**
     * Creates a new <code>AbstractOption</code>.
     *
     * @param id The object identifier.
     * @param specification The <code>Specification</code> to refer to.
     */
    public AbstractOption( String id, Specification specification )
    {
        setId( id );
        setSpecification( specification );
    }


    /**
     * Gets the string prefix that identifies the group of this
     * <code>Option</code>.
     *
     * @return The string prefix provided by the OptionGroup.
     */
    public String getGroup( )
    {
        return optionGroup;
    }

    /**
     * Set the option group prefix.
     *
     * @param group The prefix to set.
     */
    public void setGroup( String group )
    {
        optionGroup = ( group == null ) ? "" : group;
    }

    /**
     * Sets the values from another option.
     *
     * @param source The other <code>AbstractOption</code>.
     */
    protected void setValues( AbstractOption< T > source )
    {
        setId( source.getId( ) );
        setSpecification( source.getSpecification( ) );
        setValue( source.getValue( ) );
        setGroup( source.getGroup( ) );
        isDefined = source.isDefined;
    }

    /**
     * Sets the value of this option from the given string
     * representation.  Both parameters must not be null at the same
     * time.  This method does nothing.  Override it if the option has
     * a suitable string representation.
     *
     * @param valueString The string representation of the value of
     *     this <code>Option</code>.
     * @param defaultValueString The string representation of the
     *     default value of this <code>Option</code>.
     * @exception XMLStreamException if the value is invalid.
     */
    protected void setValue( String valueString, String defaultValueString )
            throws XMLStreamException
    {
        throw new XMLStreamException( "Unsupported method: setValue." );
    }

    /**
     * Generate the choices to provide to the UI.
     *
     * Override if the subclass needs to determine its choices dynamically.
     */
    public void generateChoices( )
    {
        // do nothing
    }

    /**
     * Is null an acceptable value for this option?
     *
     * Override this in subclasses where necessary.
     *
     * @return False.
     */
    public boolean isNullValueOK( )
    {
        return false;
    }


    // Interface Option

    /**
     * {@inheritDoc}
     */
    @Override
    public abstract AbstractOption< T > clone( ) throws CloneNotSupportedException;

    /**
     * Gets the value of this option.
     *
     * @return The value of this <code>Option</code>.
     */
    @Override
    public abstract T getValue( );

    /**
     * Sets the value of this option.
     *
     * @param value The new value of this <code>Option</code>.
     */
    @Override
    public abstract void setValue( T value );


    // Serialization

    protected static final String ACTION_TAG = "action";
    protected static final String DEFAULT_VALUE_TAG = "defaultValue";


    /**
     * {@inheritDoc}
     */
    @Override
    protected void readAttributes( FreeColXMLReader xr ) throws XMLStreamException
    {
        super.readAttributes( xr );

        String defaultValue = xr.getAttribute( DEFAULT_VALUE_TAG, ( String ) null );

        String value = xr.getAttribute( VALUE_TAG, ( String ) null );
        if ( defaultValue == null && value == null )
        {
            if ( ! isNullValueOK( ) )
            {
                throw new XMLStreamException( "invalid option " + getId( )
                                                      + ": no value nor default value found." );
            }
        }
        else
        {
            setValue( value, defaultValue );
        }
    }

    // Note: writeAttributes() is not needed/present.
    // - The identifier is correctly written by the super class.
    // - The default value does not need to be written in general.
    // - The value *must* be written by the implementing subclass.

    /**
     * General option reader routine.
     *
     * @param xr The <code>FreeColXMLReader</code> to read from.
     * @return An option.
     */
    protected AbstractOption readOption( FreeColXMLReader xr ) throws XMLStreamException
    {
        final Specification spec = getSpecification( );
        final String tag = xr.getLocalName( );
        AbstractOption option = null;

        if ( ACTION_TAG.equals( tag ) )
        {
            // FIXME: load FreeColActions from client options?
            logger.finest( "Skipping action " + xr.readId( ) );
            xr.nextTag( );

        }
        else if ( AbstractUnitOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new AbstractUnitOption( spec );

        }
        else if ( AudioMixerOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new AudioMixerOption( spec );

        }
        else if ( BooleanOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new BooleanOption( spec );

        }
        else if ( FileOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new FileOption( spec );

        }
        else if ( IntegerOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new IntegerOption( spec );

        }
        else if ( LanguageOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new LanguageOption( spec );

        }
        else if ( ModListOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new ModListOption( spec );

        }
        else if ( ModOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new ModOption( spec );

        }
        else if ( OptionGroup.getXMLElementTagName( ).equals( tag ) )
        {
            option = new OptionGroup( spec );

        }
        else if ( PercentageOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new PercentageOption( spec );

        }
        else if ( RangeOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new RangeOption( spec );

        }
        else if ( SelectOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new SelectOption( spec );

        }
        else if ( StringOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new StringOption( spec );

        }
        else if ( UnitListOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new UnitListOption( spec );

        }
        else if ( UnitTypeOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new UnitTypeOption( spec );

        }
        else if ( TextOption.getXMLElementTagName( ).equals( tag ) )
        {
            option = new TextOption( spec );

        }
        else
        {
            logger.warning( "Not an option type: " + tag );
            xr.nextTag( );
        }

        if ( option != null ) option.readFromXML( xr );
        return option;
    }
}
